Apparatus and method for the ligation of tissue

ABSTRACT

A novel catheter-based system which ligates the left atrial appendage (LAA) on the outside of the heart, preferably using a combination of catheters and/or instruments, e.g., a guide catheter positioned inside the left atrial appendage which may assist in locating the left atrial appendage and/or assist in the optimal placement of a ligature on the outside of the appendage, and a ligating catheter and/or instrument outside the heart in the pericardial space to set a ligating element at the neck of the left atrial appendage.

RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 10/963,371, filedOct. 11, 2004, which claims the benefit of U.S. Provisional PatentApplication Ser. Nos. 60/510,100, filed Oct. 9, 2003, and 60/528,995,filed Dec. 12, 2003. The entire content of each application isincorporated herein by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to apparatus and methods for ligating tissue, andmore particularly to ligating cardiac tissue, and even more particularlyto ligating tissue of the left atrium. In one preferred form of thepresent invention, ligation of the left atrial appendage is effectedusing a novel apparatus and method.

BACKGROUND OF THE INVENTION

Atrial fibrillation is a common problem that afflicts millions ofpatients. Unfortuately, atrial fibrillation often results in theformation of a thrombus, or clot, in the appendage of the left atrium.This presents a problem, inasmuch as the thrombus can dislodge andembolize to distant organs, resulting in adverse events such as astroke. For this reason, most patients with atrial fibrillation aretreated with a blood thinner so as to help prevent the formation of athrombus in the left atrial appendage. Unfortunately, blood thinnerspose a substantial health risk in their own right, particularly in theelderly.

An alternative treatment for atrial fibrillation is the ligation of theatrial appendage at its base. This procedure occludes the space in whichthe thrombus can form, thereby substantially eliminating the risk offorming a clot in the left atrial appendage and/or preventing a clot inthe appendage from embolizing. Surgeons have been ligating atrialappendages for years during open surgical procedures. Though effective,this approach requires general anesthesia and surgically opening thechest, which presents additional serious health risks to the patient.Therefore, such open-chest ligation of the atrial appendage is normallyrestricted to situations where the chest is already being surgicallyopened for other reasons, or where the patient is at a particularly highrisk of embolizing.

Recently, catheter-based techniques have been developed for occludingthe left atrial appendage space by placing mechanical devices inside theleft atrial appendage. This is done under fluoroscopic and/orechocardiographic guidance without the need for a major chest incisionor general anesthesia. Unfortunately, however, these techniques requirethe implantation of mechanical intracardiac devices which, over time,may result in clot formation, incomplete occluding of the appendagespace, infection, etc.

SUMMARY OF THE INVENTION

These and other issues are addressed by the present invention, whichcomprises a novel catheter-based system which ligates the left atrialappendage (LAA) on the outside of the heart, preferably using acombination of catheters and/or instruments, e.g., a guide catheterpositioned inside the left atrial appendage which may assist in locatingthe left atrial appendage and/or assist in the optimal placement of aligature on the outside of the appendage, and a ligating catheter and/orinstrument outside the heart in the pericardial space to set a ligatingelement at the neck of the left atrial appendage. As a result, thisnovel approach provides the advantages of both the open surgicalapproach (i.e., successful ligation of the atrial appendage on theoutside of the heart, while avoiding implantation of a mechanicalintracardiac device within the heart), and the catheter-based approach(i.e., providing rapid and reliable access to the left atrial appendagewithout the need for a major chest incision or general anesthesia).

The apparatus and method described herein are primarily intended toligate the left atrial appendage, however, the apparatus and method mayalso be used in the same or similar constructions to stabilize, suture,and/or ligate any other tissue in the body. By way of example but notlimitation, using the apparatus and method described herein, othertissues of the heart (such as the left ventricle) may be manipulated soas to alter the conformational geometry of the heart into a morefavorable shape.

In another form of the invention, there is provided a guide catheter foruse in conjunction with a ligating catheter for ligating tissue,comprising:

a shaft having a distal end; and

an alignment element disposed on the distal end of the shaft, whereinthe alignment element interacts with a counterpart alignment element onthe ligating catheter so as to facilitate alignment of the ligatingcatheter with the guide catheter.

In another form of the invention, there is provided a guide catheter foruse in conjunction with a ligating catheter for ligating tissue,comprising:

a shaft having a distal end; and

an expandable element connected to the distal end of the shaft, whereinthe expandable element is configured to expand to a size correspondingto the interior of the left atrial appendage.

In another form of the invention, there is provided a ligating catheterfor ligating tissue, comprising:

a hollow shaft having a distal end;

a ligating subassembly comprising a plurality of expandable armsarranged in an arcuate configuration and releasably supporting aligating element thereon, the ligating subassembly being slidablyreceived within the hollow shaft and adapted to move between (i) aretracted position wherein the expandable arms are received within thehollow shaft, and (ii) an extended position wherein the expandable armsproject from the distal end of the hollow shaft, with the expandablearms holding the ligating element radially outboard of the shaft whenthe ligating subassembly is in its second position.

In another form of the invention, there is provided a ligating catheterfor ligating tissue, comprising:

a hollow shaft having a distal end;

a ligating subassembly comprising a plurality of expandable armsarranged in an arcuate configuration and releasably supporting aligating element thereon, the ligating subassembly being slidablyreceived within the hollow shaft and adapted to move between (i) aretracted position wherein the expandable arms are received within thehollow shaft, and (ii) an extended position wherein the expandable armsproject from the distal end of the hollow shaft, with the expandablearms holding the ligating element radially outboard of the shaft whenthe ligating subassembly is in its second position;

an alignment element mounted to the shaft, wherein the alignment elementinteracts with a counterpart alignment element on a guide catheterdisposed within the tissue to be ligated; and

gripping apparatus for gripping tissue, wherein the gripping apparatuscomprises a suction tube mounted to the hollow shaft.

In another form of the invention, there is provided a system forligating tissue comprising:

a guide catheter comprising:

a shaft having a distal end; and

an alignment element disposed on the distal end of the shaft, whereinthe alignment element interacts with a counterpart alignment element ona ligating catheter so as to facilitate alignment of the ligatingcatheter with the guide catheter; and

a ligating catheter for ligating tissue, comprising:

a hollow shaft having a distal end;

a ligating subassembly comprising a plurality of expandable armsarranged in an arcuate configuration and releasably supporting aligating element thereon, the ligating subassembly being slidablyreceived within the hollow shaft and adapted to move between (i) aretracted position wherein the expandable arms are received within thehollow shaft, and (ii) an extended position wherein the expandable armsproject from the distal end of the hollow shaft, with the expandablearms holding the ligating element radially outboard of the shaft whenthe ligating subassembly is in its second position; and

an alignment element mounted to the shaft, wherein the alignment elementinteracts with counterpart alignment element on the guide catheter whenthe guide catheter is disposed within the tissue to be ligated.

In another form of the invention, there is provided a system forligating tissue comprising:

a guide catheter comprising:

a shaft having a distal end; and

an alignment element disposed on the distal end of the shaft, whereinthe alignment element interacts with a counterpart alignment element ona ligating catheter so as to facilitate alignment of the ligatingcatheter with the guide catheter; and

an expandable element connected to the distal end of the shaft, whereinthe expandable element is configured to expand to a size correspondingto the interior of the left atrial appendage; and

a ligating catheter for ligating tissue, comprising:

a hollow shaft having a distal end;

a ligating subassembly comprising a plurality of expandable armsarranged in arcuate configuration and releasably supporting a ligatingelement thereon, the ligating subassembly being slidably received withinthe hollow shaft and adapted to move between (i) a retracted positionwherein the expandable arms are received within the hollow shaft, and(ii) an extended position wherein the expandable arms project from thedistal end of the hollow shaft, with the expandable arms holding theligating element radially outboard of the shaft when the ligatingsubassembly is in its second position;

an alignment element mounted to the shaft, wherein the alignment elementinteracts with counterpart alignment element on the guide catheter whenthe guide catheter is disposed within the tissue to be ligated; and

a gripping apparatus for gripping tissue, wherein the gripping apparatuscomprises a suction tube mounted to the hollow shaft.

In another form of the invention, there is provided a method forligating tissue, comprising:

positioning a guide catheter within the interior of the tissue to beligated, wherein the guide catheter comprises an alignment element forinteracting with a counterpart alignment element on a ligating catheter;

advancing a ligating catheter so as to position a ligating element aboutthe tissue to be ligated, wherein the ligating catheter interacts withthe alignment element on the guide catheter when positioning theligating element about the tissue to be sutured; and

contracting the ligating element about the tissue, whereby to ligate thetissue.

In another form of the invention, there is provided a method forligating tissue, comprising:

providing a guide catheter and a ligating catheter, wherein the guidecatheter comprises an alignment element for interacting with acounterpart aligning element on the ligating catheter so as tofacilitate alignment of the ligating catheter with the guide catheter;

positioning the guide catheter within the tissue to be ligated;

using the alignment elements to align the ligating catheter with theguide catheter and about the tissue to be ligated; and

ligating the tissue with the ligating catheter.

In another form of the invention, there is provided a system forligating tissue comprising:

a wire extending from the interior of the left atrial appendage, throughthe side wall of the left atrial appendage, and out the pericardium;

a guide catheter slidably mounted on the wire, comprising:

a shaft having a distal end; and

an expandable element connected to the distal end of the shaft, whereinthe expandable element is configured to expand to a size correspondingto the interior of the left atrial appendage; and

a ligating catheter for ligating tissue, comprising:

a hollow shaft having a distal end; and

a ligating subassembly comprising a plurality of expandable armsarranged in an arcuate configuration and releasably supporting aligating element thereon, the ligating subassembly being slidablyreceived within the hollow shaft and adapted to move between (i) aretracted position wherein the expandable arms are received within thehollow shaft, and (ii) an extended position wherein the expandable armsproject from the distal end of the hollow shaft, with the expandablearms holding the ligating element radially outboard of the shaft whenthe ligating subassembly is in its second position.

In another form of the invention, there is provided a method forperforming a procedure on a body structure, comprising:

inserting a first device with an alignment element into the bodystructure;

positioning a second device outside of the body structure;

aligning the first device with the second device with the alignmentelement; and

performing a procedure on the body structure with the devices.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will bemore fully disclosed or rendered obvious by the following detaileddescription of the preferred embodiments of the invention, which are tobe considered together with the accompanying drawings wherein likenumbers refer to like parts.

FIG. 1 is a side view of a ligating catheter, with the catheter'sligation subassembly being disposed in a retracted position.

FIG. 2 is a view like that of FIG. 1, except that portions of theligating catheter have been shown in phantom.

FIG. 3 is an end view of the ligating catheter shown in FIG. 1.

FIG. 4 is a view like that of FIG. 1, except that the catheter'sligation subassembly is shown in an extended position.

FIG. 5 is a view like that of FIG. 4, except that portions of theligating catheter have been shown in phantom.

FIG. 6 is an end view of the ligating catheter shown in FIG. 4.

FIG. 7 is a view like that of FIG. 4, but with the ligating elementbeing contracted.

FIG. 8 is an end view of the ligating catheter shown in FIG. 7.

FIG. 9 is a view like that of FIG. 7, but with the catheter's ligationsubassembly fully retracted.

FIG. 10 is a view like that of FIG. 9, except that certain portions ofthe ligating catheter are shown in phantom.

FIG. 11 is a view like that of FIG. 10, except that the ligating elementhas been severed from the ligating catheter.

FIG. 12 is a side view showing the ligating catheter in combination witha guide catheter.

FIG. 13 is a side view of the distal tip of the guide catheter, with thecatheter's expanding element being shown in a contracted position.

FIG. 14 is a view like that of FIG. 13, except that the catheter'sexpanding element is shown in an expanded position.

FIG. 15 is a view showing the distal tip of the guide catheter placedwithin the left atrial appendage, with the catheter's expanding elementbeing shown in a contracted position.

FIG. 16 is a view like that of FIG. 15, except that the catheter'sexpanding element is shown in an expanded position.

FIG. 17 shows the guide catheter placed within the left atrialappendage, the guide catheter's expanding element placed in its expandedstate, and the ligating catheter placed over the left atrial appendage.

FIG. 18 is a view like that of FIG. 17, except that the ligatingcatheter has had its ligating element contracted about the neck of theleft atrial appendage.

FIG. 19 is a view like that of FIG. 18, except that the ligatingcatheter has been withdrawn from the surgical site.

FIG. 20 is a view like that of FIG. 19, except that the guide catheter'sexpanding element has been contracted.

FIG. 21 is a view like that of FIG. 20, except that the guide catheterhas been withdrawn from the left atrial appendage.

FIG. 22 is a schematic view showing the distal end of the guidecatheter.

FIG. 23 is a schematic view showing the guide catheter's balloon in anexpanded condition.

FIG. 24 is a schematic view showing the ligating catheter and the guidecatheter.

FIG. 25 is a schematic view showing the distal end of the ligatingcatheter.

FIGS. 26 and 27 are schematic views showing the distal ends of theligating catheter and the guide catheter orienting an end-to-end fashionthrough the use of magnets.

FIG. 28 is a schematic view showing a flared suction tube extending outof the ligating catheter's outer tube.

FIG. 29 is a schematic view showing details of the ligating subassembly.

FIG. 30 is a schematic view showing the ligating subassembly extendingover the guide catheter's inflated balloon.

FIG. 31 is a schematic view showing the ligature being drawn taut on theoutboard side of the guide catheter's balloon.

FIG. 32 is a schematic view showing a single wire track passing from theinterior of the left atrial appendage out through the pericardium,whereby a guide catheter and/or a ligating catheter may be advanced tothe surgical site.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Ligating Catheter

Looking first at FIG. 1, there is shown a ligating catheter 2 formed inaccordance with the present invention. Ligating catheter 2 comprises anelongated tube or cylinder 5, having a distal end 10 and a proximal end15. Exiting from proximal end 15 are one or more advancement/retractioncontrol elements 20, which are connected to the ligation subassembly(not shown in FIG. 1) disposed inside cylinder 5. In the constructionshown in FIG. 1, advancement/retraction control elements 20 comprisecables or wires. One or more advancement/retraction control elements 20are used to advance or withdraw the ligation subassembly (not shown inFIG. 1) disposed inside cylinder 5. In addition to the foregoing, one ormore constriction control elements 25 also exit from the proximal end ofcylinder 5. Constriction control elements 25 are also connected to theligation subassembly (not shown in FIG. 1) disposed inside cylinder 5and are used to tighten or loosen the ligating element (also not shownin FIG. 1) about a portion of the tissue or the like. In theconstruction shown in FIG. 1, constriction control elements 25 comprisecables or sutures.

Looking next at FIG. 2, outer cylinder 5 is shown in phantom. FIG. 2shows the ligation subassembly 30 in an undeployed state, i.e., withligation subassembly 30 retracted into cylinder 5. Inside cylinder 5,ligation subassembly 30 is shown having a ligating element 32 (e.g., asuture or string) that may be connected to supports or guides (such asfelt pledgets or loops 35) which help to grip and protect the tissuewhich is being ligated. Ligation subassembly 30 also includes supportingstructure 40 with struts 45. Felt pledgets 35 are disposed on the distalends of struts 45. Struts 45 are configured to expand when ligationsubassembly 30 is deployed from cylinder 5. In one preferredconstruction, struts 45 are expanded by connecting them to one anotherwith springs 50, whereby to render struts 45 self-expandable when thestruts are advanced out of the distal end of cylinder 5. Ligationsubassembly 30 is connected to advancement/retraction control elements20, whereby the ligation subassembly 30 can be advanced out of, orretracted into, cylinder 5. Furthermore, ligation subassembly 30 isconnected to constriction control elements 25, whereby the ligatingelement 32 can be constricted about a piece of tissue or the like.Advancement/retraction control elements 20, and/or constriction controlelements 25, may be connected to an appropriate handle (not shown) formanipulation by a practitioner.

Looking now at FIG. 3, there is shown the distal end 10 of cylinder 5,with the ligation subassembly 30 undeployed within outer cylinder 5,with felt pledgets 35.

Looking next at FIG. 4, a portion of the ligation subassembly 30 isshown advanced out the distal end of the cylinder 5. The ligationsubassembly 30 expands as the struts 45 exit the constrainingenvironment of tube 5 and expand away from one another. In theconstruction shown in FIGS. 1-4, struts 45 expand under the influence ofsprings 50. Ligation subassembly 30 is connected to constriction controlelements 25 which extend beyond proximal end 15 of tube 5 for actuationby the practitioner. Ligation subassembly 30 may be advanced out of thecylinder by pushing on advancement/retraction control elements 20.

FIG. 5 is similar to FIG. 4, except that the walls of cylinder 5 areshown in phantom, thereby exposing the inner workings of the device.Struts 45 are shown connected to supporting structure 40, e.g., an innersupporting ring 40.

FIG. 6 is a distal end view of the device, showing ligation subassembly30 advanced out of cylinder 5. Ligation subassembly 30 is expandedradially, with the ligating element 32 following an expanded arcuatepath about the distal ends of struts 45, with the proximal ends ofligating element 32 passing up through the center of cylinder 5 foractuation by constriction control elements 25. Thus, ligating element 32is supported by struts 45 (or other means), struts 45 may be expanded bysprings 50 (or by other means), and struts 45 may be supported bysupporting structure 40.

Looking next at FIG. 7, ligating catheter 2 is shown with ligatingelement 32 contracted. Ligating element 32 may be contracted by pullingon the proximal ends of constriction control elements 25. This actuationcauses radial contraction of the ligature loop.

FIG. 8 is a distal end view of the ligating catheter 2 with ligatingelement 32 contracted. There is radial compression of the ligature loop.Preferably, the inner supporting structure 40 remains unchanged inradial dimension, as does the distal end of the cylinder 5. Preferably,struts 45 and springs 50 collapse as the device is actuated by thepractitioner.

FIG. 9 shows struts 45 and springs 50 retracted back into cylinder 5,i.e., by pulling on the advancement/retraction control elements 20.Ligating element 32 remains in place, applying radial compression to anycaptivated tissue.

FIG. 10 is similar to FIG. 9, except that ligating catheter 2 is shownwith its cylinder 5 in phantom. Struts 45, springs 50, and supportingstructure 40 are shown retracted into cylinder 5.

FIG. 11 shows the ligating element 32 severed from constriction controlelements 25.

Guide Catheter

FIG. 12 shows the ligating catheter 2 equipped with an alignment element90. Alignment element 90 is intended for use in aligning ligatingcatheter 2 with a left atrial appendage or other target structure. Inone embodiment of the present invention, alignment element 90 comprisesa radio-opaque material and the device is placed into the desiredanatomical position by visualization, e.g., fluoroscopy.

Alternatively, and more preferably, alignment element 90 is intended towork in conjunction with a guide catheter 100, wherein the guidecatheter 100 is placed (e.g., endoluminally) within the interior of theleft atrial appendage. In this construction, guide catheter 100 alsocomprises a radio-opaque material, and alignment element 90 and guidecatheter 100 are placed in alignment by visualization.

Even more preferably, ligating catheter 2 and guide catheter 100 areprovided with physical means (e.g., magnets, male and female connectors,wires and snares, etc.) to facilitate alignment of ligating catheter 2and guide catheter 100. Thus, in one preferred construction, ligatingcatheter 2 has its alignment element 90 equipped with a reference magnet95 at its distal tip. Guide catheter 100 in turn comprises an alignmentelement 102 having a reference magnet 105 at its distal tip. Moreparticularly, with this preferred construction, ligating catheter 2 hasthe alignment element 90 which can be extended from the distal end ofcylinder 5. On the distal end of alignment element 90 is the referencemagnet 95. Alignment element 90 is put into proximity with the guidecatheter 100, which has the alignment element 102 with reference magnet105 mounted on its distal end. When these two alignment elements 90 and102 are brought into proximity with one another, magnets 95 and 105cause the alignment elements 90 and 102 to automatically align with oneanother.

For example, during left atrial appendage ligation, guide catheter 100is passed endoluminally into the left atrium appendage under visualguidance such as fluoroscopy or ultrasound. The ligating catheter 2 ispassed into the pericardium. The alignment element 90 of the ligatingcatheter is then extended from cylinder 5. Once alignment element 90 isplaced into proximity with alignment element 102, magnets 95, 105 causethe two catheters to automatically align with one another, therebycausing ligating catheter 2 to assume a desired position with respect tothe left atrial appendage. Then, ligating catheter 2 is utilized asdescribed above to ligate the left atrial appendage.

Looking next at FIG. 13, there is shown a guide catheter 100 which isprovided with an expandable element 115. Expandable element 115 isadapted to expand inside the anatomy (e.g., the left atrial appendage)so as to facilitate ligation. As noted above, guide catheter 100 has amagnet 105 mounted to its distal end. It should be noted that expandableelement 115 is shown in its non-expanded state in FIG. 13.

Looking next at FIG. 14, guide catheter 100 is shown with its expandableelement 115 in its expanded state.

FIG. 15 shows guide catheter 100, with its expandable element 115 notexpanded, and with guide catheter 100 disposed in the left atrialappendage 130.

FIG. 16 shows guide catheter 100, with its expandable element 115expanded, and with guide catheter 100 shown in the left atrial appendage130. In this respect it should be appreciated when expandable element115 is in its expanded condition within left atrial appendage 130,expandable element 115 may or may not alter the shape of the recipienttissue, depending on the size of the tissue cavity, the size of theexpanded expandable element 115, etc.

Ligating Catheter Used in Conjunction with Guide Catheter

FIG. 17 shows guide catheter 100 with its expandable element 115expanded in the left atrial appendage 130, and with ligating catheter 2expanded over the left atrial appendage 130. This aligned positioning isfacilitated through the use of alignment element 90 on ligating catheter2 and alignment element 102 on guide catheter 100. More particularly,guide catheter 100 is positioned in the left atrial appendage 130,expandable element 115 is expanded, ligating catheter 2 is positioned inthe state depicted in FIGS. 4, 5 and 6 and, using guide elements 90 and102 to align the apparatus, ligating catheter 2 is slid over the leftatrial appendage 130. Guide catheter 100 (inside the left atrialappendage) and ligating catheter 2 are aligned in this preferredconstruction using magnets 120 and 95, respectively. Significantly, byproperly sizing the apparatus vis-à-vis the anatomy, ligating element 32can be positioned at the neck of the left atrial appendage (and on theatrium side of expandable element 115) when alignment elements 90 and102 function as described.

Looking next at FIG. 18, guide catheter 100 is shown in the left atrialappendage 130, with its expandable element 115 in its expandedcondition, and ligating catheter 2 is shown actuated as describedhereinabove with respect to FIGS. 7 and 8. Due to the relativepositioning of the expanded guide catheter 100 within the left atrialappendage 130 while ligating catheter 2 is being actuated, theconstricting ligating element 32 is maintained at the neck of the leftatrial appendage 130 by the presence of the expandable element 115,thereby helping to ensure proper positioning of the ligating element 32relative to the anatomy. In other words, the presence of the expandableelement 115 inside the left atrial appendage 130 guides ligature 32 intothe desired position 135. In the example of ligating the left atrialappendage 130, the desired position 135 is where the left atrialappendage 130 meets the left atrium 140.

Looking next at FIG. 19, the apparatus is shown with guide catheter 100still in the left atrial appendage 130, but with the ligating catheter 2withdrawn, leaving the ligating element 32 deployed at the neck of theleft atrial appendage 130.

In FIG. 20, guide catheter 100 has had its expandable element 115returned to its unexpanded condition.

Looking next at FIG. 21, the left atrial appendage 130 is shown withguide catheter 100 removed from the interior of the left atrialappendage, leaving ligating element 32 at the location where the leftatrial appendage 130 meets the left atrium 140, thereby effectivelyligating the left atrial appendage from atrium 140.

One Preferred Form of Use

In one preferred form of use, guide catheter 100 is passed endoluminallyacross the atrial septum and into the left atrium. Guide catheter 100(FIG. 22) has one or more magnets 105 at its tip. Magnets 105 arepreferably so-called “rare earth” magnets composed of, for example,Neodymium-Iron-Boron,

Cobalt-Samarium or other powerful fixed magnet elements. Just behind themagnets, preferably integral with and axi-symmetric to the body of theguide catheter, is inflatable balloon 115 (FIG. 23) which, wheninflated, is spherical, conical, elliptical or of other configuration,and which preferably conforms roughly to the size and shape of the leftatrial appendage 130. The entire guide catheter 100, inclusive ofballoon 115 and magnets 105, is of a size consistent with passagethrough a commercially-available sheath (not shown), the likes of whichmay be readily passed across the atrial septum under fluoroscopicguidance using currently available tools and techniques.

In one preferred use of this system, the practitioner gains percutaneousaccess to the femoral vein using the Seldinger or other standardtechnique, and the aforementioned sheath (not shown) is introduced underfluoroscopic guidance across the atrial septum. The magnetic tip 105 ofthe guide catheter is then advanced out of the aforementioned sheath andinto the left atrial appendage, in the manner previously discussed.

The second instrument used with this iteration (i.e., the ligatingcatheter 2, as shown in FIG. 24) is introduced into the pericardialspace, between the heart and the pericardium. Pericardial access may beobtained, for example, by either a small incision below the zyphoidprocess of the sternum, or by percutaneous access using needles ordedicated systems designed for such purposes. Under fluoroscopicguidance, a wire is introduced into the pericardial space, between theheart and the pericardial sack. Similarly, pericardial access can beobtained by way of a mini-thoracotomy or by a “Chamberlain”-typeincision over the 2nd costal cartilage. Percutaneous access usingdedicated systems designed for such purposes is generally preferred asit can be done under local anesthesia. An incision over the 2nd costalcartilage, or a small incision below the zyphoid, is generally preferredto approaches that require violation of the left pleural space.

Once pericardial access is obtained, the second instrument (i.e., theligating catheter 2, as shown in FIG. 25) is introduced to the surgicalsite. In a preferred embodiment, the second instrument is preceded by aseries of dilators and sheaths that are introduced over wires. Thedilators are of a progressively increasing size culminating in theplacement of a large thin-walled tube or cylinder 5, approximately 24French or smaller, positioned such that its distal end is in the regionof the left atrial appendage. This thin-walled tube 5 then acts as adelivery cannula for advancing the ligating subassembly 30 to thesurgical site. In one iteration, the distal end 10 of the thin-walledtube 5 is deflectable by an asymmetric element that can be placed undertension. Alternatively, the thin-walled tube may have a permanentangulation or curve at its tip.

Once the thin-walled tube 5 is in position, the intrapericardial tool(i.e., the ligating subassembly 30) is advanced down the thin-walledtube 5. In a preferred embodiment, the ligating catheter 2 comprises acentral intrapericardial catheter or alignment element 90 at the end ofwhich is one or more rare-earth magnets 95, as described previously.These magnets 95 are poled to attract the ligating catheter 2 to theguide catheter 100 (previously placed in the left atrial appendage) inan end-to-end orientation. The ligating catheter 2 may be flexible or,in another embodiment, is stiff with a malleable, deflectable tip.

Coaxial to this alignment element 90, and constructed in such a mannerthat it can be advanced or withdrawn relative to either the alignmentelement 90 or the thin-walled tube 5, is a tube 150 that ends in afunnel-like or trumpet-bell flare 160. The internal diameter of thisflared tube 150 is significantly larger than the external diameter ofthe intrapericardial magnet-tipped alignment element 90 (over which theflared tube 150 slides) so as to allow vacuum to be conveyed from theback of the flared tube 150 to the distal flare 160. This flared end 160acts as a suction cup to grasp the tip of the left atrial appendage 130from outside the heart.

In a preferred embodiment, the ligating catheter's alignment element 90is advanced (FIG. 26) under fluoroscopic guidance until it engages, andcouples with, the guide catheter 100 (FIG. 27), which was previouslyplaced across the atrial septum and into the inside of the left atrialappendage. Once such alignment has been achieved, and magnetic couplingconfirmed by fluoroscopy, the flared tube 150 is advanced (FIG. 28)until it comes into contact with the outside of the left atrialappendage. Suction is then applied to the back of the flared tube 150,such that the left atrial appendage is fixed to the tip of the flaredtube by vacuum.

Over the outside of this flared tube 150, but inside the lumen of the 24French thin-walled tube 5, is a Nitinol stent-like structure or ligationsubassembly 30 that can be advanced down the thin-walled tube 5 towardthe tissue by way of a stiff catheter or other structure (i.e., theadvancement/retraction control element 20) attached to its back end.This Nitinol structure 30 is designed to expand (once released from theconstraints of the thin-walled outer tube 5) into a bell shaped crown(FIG. 29), the tips of which attach (circumferentially) the loop of asnare (i.e., the ligating element 32). In a preferred embodiment, theligating element or snare 32 is composed of polypropylene or PTFEsuture. The snare loop 32 is secured to the tips of the crown 30 in areversible, easy-to-release fashion.

Once the left atrial appendage is secured with suction, the Nitinolstructure 30, and its attached snare 32, is advanced over the flaredtube 150 toward the left atrial appendage. The flared tube 150 extends 2or 3 centimeters beyond the end of the thin-walled outer tube 5. Assuch, the Nitinol structure 30 begins to expand into a bell-shape whichfacilitates its advancement over the flared suction catheter 150, andover the left atrial appendage.

Once the Nitinol structure 30 has been advanced to the point where it isnear the base of the left atrial appendage, the balloon 115 on the guidecatheter 100 inside the appendage is inflated, preferably with acontrast material. The Nitinol structure is advanced under fluoroscopicguidance so that the tips of its bell-shaped crown 30 (and the suturesnare 32) are beyond the inter-atrial balloon (FIG. 30). The snare 32 isthen tightened by pulling on a strand of the suture that runs down thelumen of the stiff catheter 20 which is used to advance the Nitinolstructure 30 (FIG. 31). With the suture snared, the guide catheter'sballoon is deflated and the trans-septal left atrial catheter 100 isremoved. The suture snare 32 is then preferably tightened again toaccount for the space previously occupied by the inter-atrial catheter100. The Nitinol structure 30 releases away from the suture snare 32when the snare is tightened. The ligating catheter 2 is then removed andthe suture is cut at the skin.

Additional Constructions

In a preferred form of the present invention, and looking now at FIG.32, a wire 155 is passed through the left atrial appendage 130, throughthe wall of the left atrial appendage 130 and advanced through thepericardial space, whereby tip 165 of the left atrial appendage isperforated. Wire 155 can then be grasped by a catheter or snare in thepericardial space and pulled all the way through the pericardium andthen out of the body, thereby creating a single wire track on whichguide catheter 100, ligating catheter 2, and/or other devices can bepassed along from either end of wire 155. With this construction,alignment element 90 on ligating catheter 2, and/or alignment element102 on guide catheter 100 may be omitted if desired. Furthermore, withthis embodiment of the invention, guide catheter 100 may be omittedaltogether if desired.

Additionally, if desired one or more of the magnets 95 and/or 105 maycomprise an electromagnet. Such a construction permits the magneticfield to be selectively turned on and off, thus facilitating separationof the devices at the end of the procedure.

Furthermore, in the foregoing description, struts 45 are described asbeing preferably expanded by connecting them to one another with springs50, whereby to render the struts self-expandable when they are advancedout of the distal end of cylinder 5. Alternatively, struts 45 may beexpanded by other means, e.g., an expansion mechanism mounted to struts45, or by making struts 45 out of a spring material (e.g., asuperelastic material such as Nitinol), etc.

Additional Aspects of the Present Invention

In one preferred form of the invention, the novel apparatus and methoduniquely combine two or more of the following components:

(1) an elongated element such as a cylinder;

(2) an expandable element to help place the ligature over the tissue tobe ligated;

(3) the ligature;

(4) an alignment mechanism; and

(5) an expandable element that helps guide the ligature into its properposition as the ligature is deployed.

In one aspect of the invention, an alignment system is provided forpositioning a ligature delivery apparatus at a desired location around atissue structure such as the left atrial appendage.

In another aspect of the invention, a tissue expander is provided forpositioning a ligature at a desired location around a tissue structuresuch as the left atrial appendage.

And in another aspect of the invention, a radially-adjustable ligaturedelivery apparatus is provided for positioning a ligature at a desiredlocation around a tissue structure such as the left atrial appendage.This delivery apparatus may be expandable.

In still another aspect of the invention, there is provided a ligaturesystem which includes an alignment system, a tissue expander, and aradially-adjustable ligature delivery apparatus, and which is configuredto position a ligature around a tissue structure such as a left atrialappendage.

And in still another aspect of the invention, there is provided aligature system configured to position a ligature around a tissuestructure such as the left atrial appendage without opening the chest.

And in still another aspect of the invention, there is provided aligature system configured to position a ligature around a tissuestructure such as the left atrial appendage without opening the chest,using at least two catheters entering the body from remote locationssuch as a vein, artery and/or through the skin.

In another aspect of the invention, there is provided a novel systemcomprising a guide member configured for placement within the leftatrial appendage of a patient and adapted to provide a reference forpositioning a ligature at a desired location around the left atrialappendage.

In yet another aspect of the invention, there is provided a ligaturedelivery apparatus having an alignment component configured forpositioning a ligature at a desired location in response to thereference of the aforementioned guide member disposed within the leftatrial appendage.

In still another aspect of the invention, there is provided a tissueexpander configured for placement within the left atrial appendage andadapted to define a desired location for positioning a ligature.

In still another aspect of the invention, there is provided a referencecatheter having both a guide member and a tissue expander for placementwithin the left atrial appendage.

In still another aspect of the invention, there is provided aradically-adjustable ligature delivery apparatus configured for placinga ligature at a desired location around the left atrial appendage of apatient.

In still another aspect of the invention, there is provided a deliverycatheter having both an alignment component corresponding to theaforementioned guide member within the left atrial appendage of apatient and an adjustable ligature delivery apparatus for placing theligature therearound.

In still another aspect of the invention, there is provided a deliverycatheter having both an alignment component corresponding to theaforementioned guide member within the left atrial appendage of apatient and an adjustable ligature delivery apparatus for placing theligature therearound, whereby the delivery apparatus contains anexpandable element.

In still another aspect of the invention, there is provided a ligaturesystem including both a reference catheter and an alignment catheterconfigured to correspond with one another so as to place a ligature at adesired location around the left atrial appendage of a patient.

In still another aspect of the invention, there is provided a ligaturesystem including both a reference catheter and an alignment catheterconfigured to correspond with one another so as to place a ligature at adesired location around the left atrial appendage of a patient, in whicheither the reference catheter or the alignment catheter, or both,include an expandable element.

In another aspect of the invention, a device incorporating one or moreof the above-identified components is placed in proximity to the tissuewhich is to be ligated. This can be done in many ways such as underdirect visualization or under fluoroscopic, ultrasound, radiographic,CT, MRI, etc., guidance. Additionally, it can be further aligned byusing such devices as alignment strands, magnets, etc.

And in another aspect of the invention, the apparatus and method may beused to ligate the left atrial appendage as follows. Access to thepericardial space is acquired using standard techniques such as theSeldinger over-the-wire technique. For example, such device, whichpreferably comprises an elongated device such as a cylinder containingan expandable element, a ligature, and an alignment mechanism, is placedinto the pericardium over a guidewire. For example, the elongated devicecan be a large catheter in which there is an expandable element, aligature, and an alignment mechanism.

And in another aspect of the invention, a guide catheter is placed intothe left atrium using standard techniques, such as transseptally,through the veins or retrograde across the mitral valve, etc. The guidecatheter in the left atrium is then placed into the left atrialappendage under fluoroscopic guidance. At this point, the guide catheteris in the left atrial appendage and the ligating mechanism is disposedin connection with a deployment catheter in the pericardial space. Theguide catheter in the left atrium and the deployment catheter in thepericardial space are then aligned with one another. This can be doneusing a variety of techniques. For example, one or both of the devicescan be magnetized, thus allowing them to be aligned relative to oneanother using magnetic force. Alternatively, the guide catheter anddeployment catheter can be “steered” into proximity using visual orultrasonic guidance. Or the guide catheter in the left atrium canpenetrate the left atrial appendage and be “snared” by the deploymentcatheter in the pericardium. At this point, the device in thepericardium is advanced into proximity with the left atrial appendage. Aligating apparatus is then deployed from the deployment catheter andadvanced over the left atrial appendage. Preferably, the guide catheterinside the left atrium includes an expandable element such as a balloon.This expandable element is then expanded inside the left atrialappendage. In so doing, this expansion helps prevent the ligature fromslipping or migrating off of the left atrial appendage as the ligatureis tightened around the left atrial appendage. The ligature is thentightened around the left atrial appendage. The expandable elementinside the left atrium is then contracted. The guide catheter inside theleft atrial appendage is then backed out of the left atrial appendage.The procedure can be repeated as necessary. The guide catheter anddeployment catheter are then removed from the body cavity.

Alternatively, the guide catheter inside the left atrial appendage maybe removed after the ligature has been mostly placed, but before thefinal tightening of the ligature. This will allow the base of the leftatrial appendage to be completely occluded after the guide catheter iswithdrawn from the left atrial appendage.

The following text further illustrates a preferred manner for ligatingthe left atrial appendage. A trans-septal left atrial guide catheterthat has (integral to its construction) a rare-earth magnet, or otheralignment means, and an inflatable balloon, is of great utility ineffectively occluding the left atrial appendage with a snare orligature. The left atrial appendage is typically roughly conical inshape, with a slight neck or narrowing in the plane of the orifice whereit joins the left atrium proper. To effectively exclude the left atrialappendage from the outside with a ligature or snare, the snare must betightened precisely in this plane. Ideally, with the ligature tightened,the resultant left atrial geometry should be essentially spherical, withonly a slight dimple visible from the endocardial or luminal aspect atthe site of the obliterated orifice. If the snare is tightened above theplane of the orifice (toward the left atrial appendage tip), incompleteexclusion of the left atrial appendage may result in a persistentdiverticulum of left atrial appendage, which may provide a site ofstasis and thrombus formation in the fibrillating atrium. Conversely, ifthe snare is tightened below the plane of the orifice, there is a riskof injury to the circumflex coronary artery, which runs in theatrio-ventricular grove.

Snaring the left atrial appendage precisely and accurately in theoptimal plane presents several technical challenges. In someindividuals, the geometry of the left atrium and left atrial appendagemay be such that the neck or narrowing between them is poorly defined,especially from the epicardial or outer aspect. Furthermore, because theleft atrial appendage wall is thin and flexible, and the wall tensionlow (left atrial pressure is generally low, e.g., <20 mm Hg), theexternal geometry of the left atrial appendage-left atrial junction maybe of little help in constraining the snare to the correct plane duringtightening. This challenge is compounded by the fact that the anatomy ismoving vigorously, even in the fibrillating atrium, due to translationalmotion from ventricular systole. A trans-septal left atrial guidecatheter equipped with a magnetic tip and a large inflatable balloonsuch as described above enables snaring the left atrial appendage in theproper plane. More particularly, it is believed that identifying andcapturing the tip of the left atrial appendage using just anintra-pericardial instrument under fluoroscopic or echocardiographicguidance may prove prohibitively challenging. At the same time, passinga catheter across the atrial septum into the left atrium, andsubsequently positioning it in the apex of the left atrial appendage, isreadily accomplished by those skilled in the art with catheters that arecommercially available. Thus, positioning a guide catheter with arare-earth magnet (or other alignment mechanism) at the tip thereof inthe left atrial appendage is readily achievable and thereby allowsfluoroscopic guidance as to the position of the left atrial appendageapex, as well as enabling precise capturing of the apex with anintra-pericardial tool.

A balloon near the tip of the trans-septal left atrial guide cathetergreatly facilitates positioning and tightening of the snare or ligaturein the proper plane of the orifice between the left atrial appendage andleft atrium. Preferably, the balloon is designed to inflate toapproximately the size of the left atrial appendage. As the balloon isinflated, it is confined to the left atrial appendage by the neck ornarrowing at the orifice between left atrial appendage and left atrium.This may be readily confirmed by echocardiographic examination, orfluoroscopy, especially if the balloon is inflated with a contrastagent. Separate ports in the guide catheter allow the contrast agent tobe injected into the left atrial appendage and/or the left atrium properto provide further confirmation of correct position of the inflatedballoon.

The inflated balloon accentuates external geometric features at the leftatrial appendage-left atrial junction. When the spherical balloon isinflated, the flexible left atrial appendage is distended and its shapechanged (e.g., to spherical) to facilitate ligation. The junctionbetween the left atrial appendage and left atrium becomes betterdefined, like a waist of a snowman. This constrains the snare orligature to the proper plane during tightening. The balloon, andconsequently the left atrial appendage, is inflated to a pressuresignificantly higher than that of the left atrium proper. As such, thereis a significant differential in wall tension between the left atrialappendage and the left atrium. As the balloon is spherical, an attemptat snaring above the plane will result in the snare slipping off of thetense spherical surface toward the low tension, flexible neck.Radio-opaque contrast agent in the balloon, the ability to selectivelyinject contrast in the left atrial appendage and/or left atrium proper,and a radio-opaque snare or ligature greatly facilitate performing theseprocedures under fluoroscopic guidance. Once the left atrialappendage-left atrial junction is snared, the balloon is deflated andremoved and the snare tightened completely.

In general, it should be appreciated that, among other things, theinvention comprises the alignment of two devices, one within and oneoutside of a lumen, cardiac chamber, etc. Thus, the present inventioncould be used in the stomach to help with an endoscopic fundiplication.

The foregoing description is intended to illustrate preferredembodiments of the present invention. However, numerous changes may bemade to the preferred embodiments without departing from the scope ofthe present invention. Thus, one or more of the steps of the method,and/or one or more of the components of the apparatus, may be modifiedor omitted. Also, the present apparatus and method may be used to ligateany tissue or like structure in the body.

1. A method for closing a left atrial appendage of a patient's heart,comprising: advancing a first guide member transeptally into the leftatrial appendage, wherein the first guide member has a first alignmentelement for coupling with a counterpart alignment element on a secondguide member, the first alignment element located at a distal end of thefirst guide member; advancing a second guide member from the outside ofthe patient's heart into a pericardial space of the patient, wherein thesecond guide member has a second alignment element located at a distalend thereof; aligning the first and second alignment elements, such thatthe alignment members couple; advancing a ligating element over the leftatrial appendage, wherein the ligating element is advanced with respectto the second guide member; and closing the left atrial appendage usingthe ligating element.
 2. The method of claim 1, wherein the first guidemember further comprises radiopaque material, and wherein the firstguide member is visualized using fluoroscopy.
 3. The method of claim 1,wherein the first guide member is visualized using ultrasound.
 4. Themethod of claim 1, wherein the first guide member further comprises anexpandable element located near the distal end.
 5. The method of claim4, further comprising expanding the expandable element within the leftatrial appendage before closing the left atrial appendage using theligating element.
 6. The method of claim 4, wherein the expandableelement is an inflatable balloon.
 7. The method of claim 1, wherein thefirst and second alignment elements are magnets.
 8. The method of claim1, wherein the pericardial space is accessed by making an incision belowthe xyphoid process.
 9. The method of claim 1, wherein the pericardialspace is accessed by making an incision over the second costalcartilage.
 10. The method of claim 1, wherein the ligating elementcomprises a nitinol structure with a suture.
 11. The method of claim 1,wherein the ligating element comprises a suture.
 12. The method of claim11, wherein the suture is made from polypropylene or PTFE.
 13. Themethod of claim 1, wherein the first guide member is coupled to anexpandable element.
 14. The method of claim 13, wherein the expandableelement is an inflatable balloon.
 15. The method of claim 1, wherein thepericardial space is accessed by using a series of dilators.